Since the advent of computers, various types of hardware have been associated with computers. Examples of hardware include devices, processors, and thermal zones, among other things. Examples of devices include, but are not limited to, hard drives, tape drives, tape controllers, and Small Computer System Interface (SCSI) controllers. Thermal zones frequently include a set of devices that are used for sensing the temperature of various other pieces of hardware and/or for cooling other pieces of hardware.
Frequently actions pertaining to hardware need to be performed, for example, when something happens to the hardware. In this case, an administrator or a user may interact with the computer to indicate what action they want performed and what hardware they want the action performed on. Additionally, the system itself may detect that an action needs to be taken with regards to hardware. Examples of these actions include, but are not limited to, deleting hardware from the computer, adding hardware to the computer, causing a disk drive to read or eject a disk, dynamic reconfiguration of hardware, etc.
Platforms that run on Intel and AMD processors use event notification interfaces (referred to hereinafter as “legacy event notification interfaces”) defined by the Advanced Configuration and Power Interface (ACPI) specification. These platforms support operating systems that include, but are not limited to, Linux, Windows™, HP-UX™. With ACPI, the firmware on the computer requests that the action be performed on the hardware by a legacy event notification interface to create an event notification (referred to hereinafter as a “legacy event notification”). The firmware communicates the legacy event notification to the operating system of the computer and the operating system performs the action on the hardware.
It is essential that the operating system be able to differentiate one type of action from another type of action. The legacy event notification interface uses a 1 byte notification value to differentiate one type of action, and hence to differentiate between the legacy event notification interfaces and the respective event notifications. The value for the notification value is determined by an ACPI standards committee.
The legacy event notification interfaces provided by ACPI require that companies divulge confidential information or intellectual property (IP) to the ACPI standards committee in order to obtain a notification value. Also, the committee is mostly concerned with developing interfaces for features that can be used by a wide range of companies and products. These features are commonly known as “baseline features.” Therefore, the committee is not motivated to help companies develop interfaces for features that are unique to their products or model line of products. These features are known as “value added features.” Third, the notification value is limited to 1 byte and therefore, there is a limit on the number of legacy event notification interfaces that the ACPI standards committee can authorize.